Electricity storage unit

Abstract

The utility model relates to an electric power storage unit. The utility model aims to improve the infiltration speed of electrolyte. A power storage cell includes a case, an electrode body, an insulating film, and an electrolyte solution. The case accommodates the electrode body, the insulating film, and the electrolyte. The electrode body has an upper surface, a lower surface, and a peripheral surface. A liquid injection hole is formed in the surface, opposite to the upper surface, of the shell. The peripheral surface connects the upper surface and the lower surface. The peripheral surface includes a first region and a second region. The first region is covered with an insulating film. The second region is not covered by the insulating film. The second region extends from the upper surface to the lower surface. The second region has a smaller area than the first region.

Description

Technical Field

[0001] The present utility model relates to a power storage unit. Background Art

[0002] Japanese Patent Application Laid-Open No. 2016-100270 discloses an insulating tape joined to the outermost periphery of an electrode body. Summary of the Utility Model

[0003] The power storage unit includes a housing and an electrode body. The housing houses the electrode body. After housing the electrode body, an electrolytic solution is injected into the housing. From the viewpoint of the energy density of the power storage unit, it is required to reduce the clearance between the housing and the electrode body. The smaller the clearance, the more likely the flow path of the electrolytic solution around the electrode body will be reduced. Therefore, there is a tendency for it to take a long time for the electrolytic solution to cover the entire electrode body. That is, there is room for improvement in the impregnation speed of the electrolytic solution.

[0004] The object of the present utility model is to improve the impregnation speed of the electrolytic solution.

[0005] Hereinafter, the technical solutions and effects of the present utility model will be described. However, the mechanism of action includes assumptions. The mechanism of action does not limit the technical scope of the present utility model.

[0006] 1. A power storage unit includes a housing, an electrode body, an insulating film, and an electrolytic solution. The housing houses the electrode body, the insulating film, and the electrolytic solution. The electrode body has an upper surface, a lower surface, and a peripheral surface. In the housing, a liquid injection hole is provided on the surface opposite to the upper surface. The peripheral surface connects the upper surface and the lower surface. The peripheral surface includes a first region and a second region. The first region is covered with the insulating film. The second region is not covered with the insulating film. The second region extends from the upper surface to the lower surface. The area of the second region is smaller than that of the first region.

[0007] The electrolytic solution injected from the liquid injection hole is supplied to the upper surface of the electrode body. Due to the thickness of the insulating film, a gap can be formed between the second region and the housing. Through this gap serving as the flow path of the electrolytic solution, the electrolytic solution can be quickly supplied from the upper surface to the lower surface. Thus, an improvement in the impregnation speed can be expected.

[0008] 2. The power storage unit of the above "1" may also include, for example, the following solutions.

[0009] The power storage unit further includes an insulating member. In the housing, the insulating member is disposed at a position opposite to the second region.

[0010] The insulating member can electrically insulate the second region from the housing.

[0011] 3. The power storage unit of the above "1" or "2" may also include, for example, the following solutions.

[0012] The second region is disposed below the liquid injection hole.

[0013] By arranging the second region below the liquid injection hole, an increase in the infiltration speed can be expected.

[0014] 4. The power storage unit according to any one of the above "1" to "3" may also include, for example, the following solutions.

[0015] The power storage unit further includes an insulating tape. In the circumferential direction of the circumferential surface, the second region is sandwiched by the first regions. The insulating tape extends in a manner that spans the second region and bridges the first regions to each other.

[0016] The insulating tape can electrically insulate the second region from the housing.

[0017] 5. The power storage unit according to any one of the above "1" to "4" may also include, for example, the following solutions.

[0018] The insulating film is in a strip shape.

[0019] The strip-shaped insulating film is suitable for attaching to the circumferential surface. By the insulating film being in a strip shape, an increase in productivity can be expected, for example.

[0020] 6. The power storage unit according to any one of the above "1" to "5" may also include, for example, the following solutions.

[0021] The insulating film is wound around the circumferential surface.

[0022] 7. The power storage unit according to any one of the above "1" to "6" may also include, for example, the following solutions.

[0023] The insulating film has a length direction and a width direction. The width direction is orthogonal to the length direction. The dimension in the length direction is shorter than the circumference of the circumferential surface.

[0024] By the length dimension of the insulating film being shorter than the circumference of the circumferential surface, when the insulating film is wound around the circumferential surface, a gap can be formed between the start end and the end end of the insulating film. That is, the second region can be formed.

[0025] 8. The power storage unit according to any one of the above "1" to "7" may also include, for example, the following solutions.

[0026] The electrode body has a cubic outer shape. The electrode body is a stacked type.

[0027] 9. The power storage unit according to any one of the above "1" to "8" may also include, for example, the following solutions.

[0028] The circumferential surface is composed of a first region and a second region.

[0029] The following describes an embodiment of the present invention (hereinafter referred to as "this embodiment"). However, this embodiment does not limit the technical scope of the present invention. This embodiment is illustrative in all aspects. This embodiment is non-restrictive. The technical scope of the present invention includes all changes within the meaning and scope equivalent to those described in the claims. For example, it is intended from the outset to include a solution that extracts any solution from this embodiment and combines them arbitrarily.

[0030] The above and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic perspective view showing an example of a power storage unit in this embodiment.

[0032] Figure 2 This is a first schematic cross-sectional view showing an example of the power storage unit in the present embodiment.

[0033] Figure 3 This is a schematic diagram showing an example of an electrode body in this embodiment.

[0034] Figure 4 It is a second schematic cross-sectional view showing an example of the power storage unit in the present embodiment.

[0035] Figure 5 This is a schematic cross-sectional view showing an example of an electrode body according to the present embodiment. DETAILED DESCRIPTION

[0036] 1. Explanation of terms

[0037] "Having", "including", "having" and their variations are open-ended terms. In addition to the essential elements, an open-ended term may or may not contain additional elements. The statement "consisting of..." is a closed-ended term. However, even a solution expressed in a closed-ended term may usually contain incidental impurities or additional elements that are not related to the technology of the utility model. The statement "consisting essentially of..." is a semi-closed term. In a semi-closed term, it is allowed to add elements that have no substantial effect on the basic and new characteristics of the technology of the utility model.

[0038] Geometric terms should not be understood in a strict sense. As geometric terms, for example, "parallel", "perpendicular", "orthogonal", etc. can be exemplified. For example, "parallel" can also deviate slightly from the "parallel" in the strict sense. For example, geometric terms can include tolerances, errors, etc. in design, operation, manufacturing, etc. The dimensional relationships in each figure are sometimes inconsistent with the actual dimensional relationships. To help readers understand, sometimes the dimensional relationships in each figure are changed. For example, sometimes the length, width, thickness, etc. are changed. Also, sometimes a part of the structure is omitted.

[0039] For numerical ranges such as "m to n%", unless otherwise specified, the upper limit value and the lower limit value are included. That is, "m to n%" represents a numerical range of "m% or more and n% or less". In addition, "m% or more and n% or less" includes "more than m% and less than n%". "Or more" and "or less" are represented by the inequality sign "≤" with an equal sign. "More than" and "less than" are represented by the inequality sign "<" without an equal sign. It is also possible to use any value selected from within the numerical range as a new upper limit value or lower limit value. For example, it is also possible to set a new numerical range by arbitrarily combining the values within the numerical range and the values described in other parts of this specification, in tables, in figures, etc.

[0040] All numerical values are modified by the term "about". The term "about" can represent, for example, ±5%, ±3%, ±1%, etc. All numerical values can be approximate values that can vary according to the utilization form of the technology of the present utility model. All numerical values can be expressed in significant figures. Unless otherwise specified, the measured value can be the average value of multiple measurements. The number of measurements can be 3 or more, can be 5 or more, or can be 10 or more. Generally, it is expected that the more the number of measurements, the higher the reliability of the average value. The measured value can be rounded based on the number of significant figures. The measured value can include, for example, errors such as the detection limit of the measuring device.

[0041] 2. Energy storage unit

[0042] Figure 1 is a schematic perspective view showing an example of the energy storage unit in this embodiment. The energy storage unit 1 can also have, for example, a height direction, a width direction, and a thickness direction. The height direction, the width direction, and the thickness direction are orthogonal to each other. The "height direction" is Figure 1 the like of the H direction. The "width direction" is Figure 1 the like of the W direction. The "thickness direction" is Figure 1 the like of the D direction. The height direction can also be parallel to the vertical direction, for example. The width direction and the thickness direction can also be parallel to the horizontal direction, for example. "Height" represents the dimension in the height direction. "Width" represents the dimension in the width direction. "Thickness" represents the dimension in the thickness direction or the thickness of the object.

[0043] Figure 2 FIG. 1 is a first schematic cross-sectional view showing an example of the power storage unit in the present embodiment. Figure 2 The cross-section perpendicular to the thickness direction is shown. The power storage unit 1 includes a housing 200, an electrode body 100, an insulating film 101, and an electrolytic solution (not shown). The electrolytic solution is a liquid electrolyte. The electrolytic solution may also contain, for example, an organic solvent and a lithium salt.

[0044] 3. Electrode Body, Insulating Film

[0045] The electrode body 100 may have, for example, a cubic outer shape. The electrode body 100 may have, for example, a rectangular parallelepiped outer shape. The electrode body 100 may be, for example, a flat rectangular parallelepiped shape.

[0046] The "first aspect ratio" represents the ratio of the width of the electrode body 100 to the height. The first aspect ratio may be, for example, any one of 1 or more, 1.5 or more, 2 or more, 2.5 or more, 3 or more, 5 or more, and 10 or more. The first aspect ratio may be, for example, any one of 10 or less, 5 or less, 3 or less, 2.5 or less, 2 or less, and 1.5 or less. The "second aspect ratio" represents the ratio of the thickness of the electrode body 100 to the height. The second aspect ratio may be, for example, any one of 0.1 or more, 0.2 or more, 0.3 or more, 0.5 or more, and 1 or more. The second aspect ratio may be, for example, any one of 1 or less, 0.5 or less, 0.3 or less, and 0.2 or less.

[0047] Figure 3 FIG. 2 is a schematic view showing an example of the electrode body in the present embodiment. The electrode body 100 has an upper surface 100a, a lower surface 100b, and a peripheral surface 100c. The upper surface 100a, the lower surface 100b, and the peripheral surface 100c may be flat surfaces or may be uneven surfaces. The upper surface 100a may be parallel to the lower surface 100b. The peripheral surface 100c connects the upper surface 100a and the lower surface 100b. The peripheral surface 100c may include 4 planes. Each plane may be rectangular.

[0048] Figure 4 FIG. 3 is a second schematic cross-sectional view showing an example of the power storage unit in the present embodiment. Figure 4 The cross-section perpendicular to the height direction is shown. The peripheral surface 100c includes a first region R1 and a second region R2. The peripheral surface 100c may be composed of the first region R1 and the second region R2.

[0049] The first region R1 is covered with the insulating film 101. The insulating film 101 may be attached to the first region R1. The insulating film 101 may be bonded to the first region R1. For example, the insulating film 101 may be bonded to the first region R1 using an adhesive material. The first region R1 may be a continuous region. The first region R1 may also be divided into a plurality of parts.

[0050] The second region R2 is not covered by the insulating film 101. The second region R2 may be a continuous region. The second region R2 may also be divided into multiple parts. The second region R2 is sandwiched by the first region R1. In the circumferential direction of the circumferential surface 100c, the second region R2 may also be sandwiched by, for example, the start end of the first region R1 and the terminal end of the first region R1. The second region R2 extends in the height direction. The second region R2 extends from the upper surface 100a to the lower surface 100b.

[0051] The area of the second region R2 is smaller than that of the first region R1. The ratio of the area of the second region R2 to the area of the first region R1 may be, for example, any one of 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, 0.1 or less, 0.05 or less, 0.03 or less, and 0.01 or less. The ratio of the area of the second region R2 to the area of the first region R1 may also be, for example, any one of 0.001 or more, 0.005 or more, 0.01 or more, 0.05 or more, and 0.1 or more.

[0052] Furthermore, in the case where the first region R1 is divided into multiple parts, the total area of all parts is regarded as the area of the first region R1. The same applies to the second region R2.

[0053] The insulating film 101 has a length direction and a width direction. The width direction is orthogonal to the length direction. The width direction of the insulating film 101 is parallel to the height direction. The insulating film 101 may be, for example, strip-shaped. The dimension of the insulating film 101 in the length direction may also be shorter than the circumference of the circumferential surface 100c. By winding the insulating film 101 shorter than the circumference around the circumferential surface 100c, a continuous first region R1 can be formed.

[0054] The thickness of the insulating film 101 may be, for example, any one of 1 μm or more, 5 μm or more, 10 μm or more, 50 μm or more, 100 μm or more, 500 μm or more, and 1 mm or more. The thickness of the insulating film 101 may also be, for example, any one of 2 mm or less, 1 mm or less, 500 μm or less, 100 μm or less, 50 μm or less, 10 μm or less, and 5 μm or less. The thickness of the insulating film 101 may be uniform or locally different. One sheet of the insulating film 101 may be used alone. Multiple sheets of the insulating film 101 may also be used. For example, multiple sheets of the insulating film 101 may be laminated. For example, multiple sheets of the insulating film 101 may also be spliced.

[0055] The insulating film 101 has electrical insulation properties. As long as it has electrical insulation properties, the insulating film 101 can contain any material. For example, the insulating film 101 can also be made of resin. For example, the insulating film 101 can also contain at least one selected from polypropylene (PP), polyimide (PI), polyethylene (PE), polyethylene terephthalate (PET), and polyphenylene sulfide (PPS).

[0056] The electricity storage unit 1 can also include a first insulating member 102. The area of the first insulating member 102 can also be larger than that of the second region R2. For example, the ratio of the area of the first insulating member 102 to the area of the second region R2 can be any one of 1.01 or more, 1.1 or more, 1.2 or more, 1.5 or more, and 2 or more. For example, the ratio of the area of the first insulating member 102 to the area of the second region R2 can be any one of 2.5 or less, 2.0 or less, and 1.5 or less.

[0057] For example, the first insulating member 102 can also be disposed on the surface of the housing 200. For example, in the housing 200, the first insulating member 102 can also be disposed at a position opposite to the second region R2. For example, the first insulating member 102 can also include an insulating coating or the like. For example, in the housing 200, an insulating coating can also be applied at a position opposite to the second region R2. The insulating coating can also include, for example, ceramic powder, resin powder, resin film, etc.

[0058] For example, the first insulating member 102 can also include an insulating tape or the like. The insulating tape can extend, for example, in a manner that straddles the second region R2 and bridges the first regions R1 to each other. The insulating tape can extend, for example, in a manner that connects the start end and the terminal end of the first region R1. The insulating tape can be attached to the insulating film 101 or can also be attached to the housing 200. For example, the insulating tape can be thinner than the insulating film 101. For example, the ratio of the thickness of the insulating tape to the thickness of the insulating film 101 can be any one of 1 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, and 0.5 or less. For example, the ratio of the thickness of the insulating tape to the thickness of the insulating film 101 can be any one of 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, and 0.5 or more.

[0059] The insulating tape can also include, for example, a base material layer and an adhesive layer. The adhesive layer is laminated on the base material layer. The base material layer can include, for example, the same material as the insulating film 101. The thickness of the base material layer can be, for example, 1 to 100 μm. The adhesive layer can contain, for example, at least one selected from acrylic adhesives, silicone adhesives, polyurethane adhesives, and rubber adhesives.

[0060] 4. Laminated Structure

[0061] The electrode body can have an arbitrary laminated structure. The electrode body can be, for example, a wound type. The electrode body can also be, for example, a laminated type.

[0062] Figure 5 It is a schematic cross-sectional view showing an example of the electrode body of the present embodiment. Figure 5 The electrode body 100 in is a laminated type. The electrode body 100 includes one or more first electrodes 110, one or more second electrodes 120, and one or more separators 130. In the thickness direction, the first electrodes 110 and the second electrodes 120 are alternately laminated. That is, the thickness direction of the power storage unit 1 is parallel to the lamination direction of the first electrodes 110 and the second electrodes 120. The number of the first electrodes 110 and the second electrodes 120 can each be any one of 2 or more, 5 or more, 10 or more, 50 or more, and 100 or more. The number of the first electrodes 110 and the second electrodes 120 can each be any one of 200 or less, 100 or less, 50 or less, 10 or less, and 5 or less.

[0063] The polarity of the second electrode 120 is different from that of the first electrode 110. For example, the first electrode 110 can be a positive electrode and the second electrode 120 can be a negative electrode. For example, the first electrode 110 can also be a negative electrode and the second electrode 120 can be a positive electrode.

[0064] For example, the first electrode 110 can also include a first current collector 112 and a first active material layer 114. The first current collector 112 can include, for example, a metal foil or the like. The metal foil can contain, for example, Al, Cu, Ni, Ti, Fe, etc. The first active material layer 114 is disposed on the surface of the first current collector 112. The first active material layer 114 can be disposed only on one side of the first current collector 112. The first active material layer 114 can also be disposed on both sides of the first current collector 112. The first active material layer 114 contains a positive electrode active material or a negative electrode active material. The positive electrode active material can contain, for example, a lithium nickel composite oxide or the like. The negative electrode active material can contain, for example, graphite, SiO, Si, etc.

[0065] The second electrode 120 may also include, for example, a second current collector 122 and a second active material layer 124. The second current collector 122 may also include, for example, a metal foil or the like. The second active material layer 124 is disposed on the surface of the second current collector 122. The second active material layer 124 may be disposed only on one side of the second current collector 122. The second active material layer 124 may also be disposed on both sides of the second current collector 122. The second active material layer 124 contains a positive electrode active material or a negative electrode active material. The second active material layer 124 may have the same area as the first active material layer 114, or may have a different area. For example, the area of the second active material layer 124 may be larger than the area of the first active material layer 114. The ratio of the area of the second active material layer 124 to the area of the first active material layer 114 may be any one of, for example, 1.01 or more, 1.05 or more, and 1.1 or more. The ratio of the area of the second active material layer 124 to the area of the first active material layer 114 may be any one of, for example, 1.1 or less, 1.05 or less, and 1.01 or less.

[0066] The separator 130 has electrical insulation. The separator 130 is porous. The separator 130 may also include, for example, a microporous membrane made of polyolefin or the like. The thickness of the separator 130 may be any one of, for example, 5 to 50 μm, 5 to 30 μm, and 5 to 15 μm. The separator 130 separates the first electrode 110 from the second electrode 120. The separator 130 may be two or more. For example, the separator 130 may be inserted one by one between the first electrode 110 and the second electrode 120.

[0067] The separator 130 may also be one, for example. For example, the separator 130 may include a hairpin bend portion 135. In the hairpin bend portion 135, the separator 130 is folded into a hairpin shape. The hairpin shape may be expressed as, for example, "serpentine shape", "accordion shape", etc.

[0068] The hairpin bend portion 135 includes a flat portion 131 and a folded-back portion 132. In the flat portion 131, the separator 130 extends in a planar shape. In the folded-back portion 132, the separator 130 is folded back. The folded-back portion 132 is disposed at both ends in the height direction. The separator 130 is folded back in such a manner as to alternately sandwich the first electrode 110 or the second electrode 120. The flat portion 131 sandwiches the first electrode 110 or the second electrode 120. For example, the separator 130 may further include an outer peripheral portion 136. The outer peripheral portion 136 may be wound so as to surround the hairpin bend portion 135. Furthermore, at both ends in the width direction, the hairpin bend portion may be formed by folding back the separator 130.

[0069] 5. Housing

[0070] The housing 200 houses the electrolyte and the electrode body 100. The housing 200 can also be airtight. The housing 200 can be sealed. For example, the housing 200 can also include a can 210 and a lid 220. The can 210 has an opening. The opening opens in the height direction. The opening can, for example, also open vertically upward. The can 210 can, for example, also be made of metal. The can 210 can, for example, also contain Al or the like. The can 210 can, for example, also include a bottom wall 212 and a peripheral wall 214. The bottom wall 212 can, for example, also be flat. The planar shape of the bottom wall 212 can, for example, also be rectangular. The peripheral wall 214 stands up from the bottom wall 212. The peripheral wall 214 can, for example, also be a four-sided tubular shape. The width of the peripheral wall 214 can be greater than the thickness of the peripheral wall 214. The height of the peripheral wall 214 can be greater than the thickness of the peripheral wall 214. Furthermore, the "thickness of the peripheral wall 214" here represents the outer dimension of the housing 200 in the thickness direction.

[0071] The lid 220 closes the opening of the can 210. The lid 220 can be welded to the peripheral wall 214. The lid 220 can, for example, also be flat. The lid 220 can, for example, also be made of metal. The lid 220 can, for example, also contain Al or the like. The lid 220 can also include, for example, a pressure release valve 222 and a sealing member 224.

[0072] The pressure release valve 222 can, for example, also be disposed near the center of the lid 220. The pressure release valve 222 releases the internal pressure of the housing 200. If the internal pressure becomes above a set value, the pressure release valve 222 can open. The sealing member 224 seals the liquid injection hole 221. The electrolyte can be injected from the liquid injection hole 221.

[0073] The inner surface of the lid 220 faces the upper surface 100a of the electrode body 100. That is, in the housing 200, the liquid injection hole 221 is provided on the surface facing the upper surface 100a. The liquid injection hole 221 can have a specific positional relationship with the second region R2. The second region R2 can be disposed below the liquid injection hole 221. For example, the angle formed by the straight line connecting the second region R2 and the liquid injection hole 221 with the height direction can be 60° or less. The formed angle can, for example, also be any one of 45° or less, 30° or less, 15° or less, 5° or less, 3° or less, and 1° or less. The second region R2 can, for example, also be disposed directly below the liquid injection hole 221. For example, in the width direction, the position of the liquid injection hole 221 and the position of the second region R2 can coincide.

[0074] A pair of external terminals 300 are fixed to the lid 220. The external terminals 300 are connected to the first electrode 110 or the second electrode 120. The external terminals 300 can, for example, also be made of metal. The external terminals can also contain Al, Cu, Ni, etc. The external terminals 300 can, for example, also have a rectangular parallelepiped shape. The external terminals 300 can also be connected to a bus bar (not shown).

[0075] A pair of connecting members 400 connect the electrode tab to the external terminal 300. The electrode tab refers to the first electrode tab 116 or the second electrode tab 126. The two connecting members 400 may also have substantially the same structure.

[0076] For example, the connecting member 400 may also include a collector tab 410, a sub-tab 420, and a connecting pin 430. The collector tab 410 includes a side portion 412 and an upper portion 414. The side portion 412 is located on the side of the electrode body 100 in the width direction. The upper portion 414 is located above the electrode body 100. The upper portion 414 extends inward from the upper end of the side portion 412 in the width direction.

[0077] The sub-tab 420 connects a plurality of electrode tabs to the collector tab 410. The sub-tab 420 may also include a first end portion 422 and a second end portion 424. The first end portion 422 is connected to a plurality of electrode tabs. The second end portion 424 is connected to the side portion 412.

[0078] The connecting pin 430 connects the collector tab 410 to the external terminal 300. The connecting pin 430 connects the upper portion 414 and the external terminal 300. For example, the lower end portion of the connecting pin 430 may be inserted through a through hole provided in the upper portion 414.

[0079] The second insulating member 500 insulates the housing 200 from the connecting member 400. For example, the second insulating member 500 may also include a first portion 510, a second portion 520, a third portion 530, and a fourth portion 540.

[0080] The first portion 510 is fixed to the upper surface of the cover 220. The first portion 510 is disposed between the cover 220 and the external terminal 300. The second portion 520 is fixed to the lower surface of the cover 220. The second portion 520 is disposed between the cover 220 and the upper portion 414. The second portion 520 is disposed between the cover 220 and the lower portion of the connecting pin 430. The third portion 530 is disposed between the connecting pin 430 and the cover 220. The third portion 530 is cylindrical. The third portion 530 surrounds the connecting pin 430. Through holes are provided in the first portion 510, the second portion 520, and the third portion 530. The connecting pin 430 is inserted through the through holes.

[0081] The fourth portion 540 is plate-shaped. It is fixed to the lower surface of the upper portion 414. The fourth portion 540 is disposed above the electrode body 100. In the fourth portion 540, through holes are provided below the pressure release valve 222. In the fourth portion 540, through holes are also provided below the liquid injection hole 221.

Claims

1. A power storage unit, characterized in that: It includes a shell, an electrode body, an insulating film and an electrolyte. The housing contains the electrode body, the insulating film, and the electrolyte. The electrode body has an upper surface, a lower surface and a peripheral surface, The housing is provided with a liquid injection hole on a surface opposite to the upper surface. The peripheral surface connects the upper surface and the lower surface, The peripheral surface includes a first area and a second area, The first region is covered by the insulating film, The second region is not covered by the insulating film, The second region extends from the upper surface to the lower surface, and The second region has a smaller area than the first region.

2. The power storage unit according to claim 1, characterized in that: Also includes an insulating member, and The insulating member is arranged in the housing at a position facing the second region.

3. The power storage unit according to claim 1, characterized in that: The second region is disposed below the liquid injection hole.

4. The power storage unit according to claim 1, characterized in that: Also includes insulation tape, In the circumferential direction of the peripheral surface, the second region is sandwiched by the first region, and The insulating tape extends across the second region and bridges the first regions.

5. The power storage unit according to claim 1, characterized in that: The insulating film is in a strip shape.

6. The power storage unit according to claim 1, characterized in that: The insulating film is wound around the peripheral surface.

7. The power storage unit according to claim 1, characterized in that: The insulating film has a length direction and a width direction, The width direction is orthogonal to the length direction, and The dimension in the longitudinal direction is shorter than the circumference of the peripheral surface.

8. The power storage unit according to claim 1, characterized in that: The electrode body has a cubic shape, and The electrode body is of a stacked type.

9. The power storage unit according to any one of claims 1 to 8, characterized in that: The peripheral surface is composed of the first region and the second region.

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